Hydrographic Office Research Articles

Antarctic Treaty System Ready for a Challenge

In their Policy Forum “Challenges to the future conservation of the Antarctic” (13 July, p. [158][1]), S. L. Chown et al. discuss concerns about the Antarctic Treaty System's (ATS's) ability to navigate future challenges. We believe ATS has demonstrated that it is both robust and adaptable. ![Figure][2] United. Treaty nation flags fly over the South Pole. CREDIT: PETTY OFFICER 2ND CLASS JOHN K. SOKOLOWSKI/U.S. NAVY Chown et al. raise the issue of marine resource harvesting, biological prospecting, and potential mineral and hydrocarbon exploitation. The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) regulates the harvesting of marine resources in the Southern Ocean, and it has arguably the most highly developed system for ecosystem-based management of any international agreement ([ 1 ][3]). Underpinning CCAMLR's decision-making processes is the precautionary approach which, as it has evolved, has set very conservative catch limits on fish stocks and provided other mechanisms for reducing harvesting impacts. The Southern Ocean krill fishery is arguably the largest underexploited fishery in the world. For many years, CCAMLR has been developing mechanisms in advance of projected escalation of interest in the fishery, including setting precautionary catch limits, establishing small-scale management areas, and invoking trigger points where, when a predesignated catch is exceeded, additional conservation measures will apply. In their discussion of the submissions of several Antarctic claimant states to the Commission on the Limits of the Continental Shelf (CLCS), Chown et al. have misconstrued both the actions of those Antarctic Treaty Parties and the effects of those actions. All Antarctic Treaty Parties are bound by the Antarctic mining ban ([ 2 ][4]). Submission of data to the CLCS in relation to Antarctic or other continental shelves has no bearing on that ban or a party's obligation to uphold it. Mitigating unacceptable human impacts in Antarctica is a substantial focus for the Antarctic Treaty Consultative Parties, as Chown et al. note. There is no evidence that human interest in Antarctica will outpace the capacity of the ATS to respond. The historically steady climb in Antarctic tourism numbers from the 1990s has been reversed since the 2008 financial crisis ([ 3 ][5]) and also since the International Maritime Organization introduced a ban on the use and carriage of heavy and intermediate fuel into the Antarctic Treaty Area in 2011 ([ 4 ][6]). Tourism is subject to ongoing monitoring, oversight, and management, mainly through the International Association of Antarctica Tour Operators (IAATO)—an organization mindful of the extraordinary responsibilities it carries for maintaining the integrity of the pristine Antarctic environment. Local impact is minimized by a system of site guidelines and rules about behavior ashore—the latter originally adopted by IAATO in its by-laws and later formalized by the ATS. The Antarctic Treaty Consultative Parties have addressed past challenges firmly and overtly within the Antarctic Treaty's twin pillars of peace and science ([ 5 ][7]). Reforms to the operation of the Antarctic Treaty Consultative Meeting, increased opportunities for engagement with relevant international organizations, and the presence of nongovernmental organizations as observers to ATS meetings and as members of national delegations since the mid-1980s all work to strengthen the institutional resilience of the ATS. The number of parties acceding to instruments of the Antarctic Treaty System has steadily increased (including, notably, Malaysia and Pakistan in 2011). At the same time, the Antarctic Treaty Consultative Parties have increased engagement with relevant international organizations: among them, the UN Food and Agriculture Organization regarding IUU fishing; the International Hydrographic Office in relation to charting Antarctic waters; and the International Maritime Organization in the development of the Polar Shipping Code. We concur that the challenges facing the region defy complacency. The quickening pace of global change requires scientists and policymakers to work together. With this as a fundamental underpinning for future action, we believe the ATS is well placed to meet these challenges. 1. [↵][8] 1. A. Constable , Fish Fisheries 12, 138 (2011). [OpenUrl][9][CrossRef][10][Web of Science][11] 2. [↵][12] Article 7, Protocol on Environmental Protection to the Antarctic Treaty, Antarctic Treaty Secretariat ([www.ats.aq/e/ep.htm][13]). 3. [↵][14] International Association of Antarctica Tour Operators, Tourism Statistics ( ). 4. [↵][15] Annex I, Chapter 9, “Special requirements for the use or carriage of oils in the Antarctic area,” International Convention for the Prevention of Pollution from Ships (MARPOL) (International Maritime Organization Resolution MEPC.189(60), 26 March 2010). 5. [↵][16] Articles I and III of the Antarctic Treaty, Antarctic Treaty Secretariat ([www.ats.aq/documents/ats/treaty_original.pdf][17]). [1]: /lookup/doi/10.1126/science.1222821 [2]: pending:yes [3]: #ref-1 [4]: #ref-2 [5]: #ref-3 [6]: #ref-4 [7]: #ref-5 [8]: #xref-ref-1-1 View reference 1 in text [9]: {openurl}?query=rft.jtitle%253DFish%2BFisheries%26rft.volume%253D12%26rft.spage%253D138%26rft_id%253Dinfo%253Adoi%252F10.1111%252Fj.1467-2979.2011.00410.x%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [10]: /lookup/external-ref?access_num=10.1111/j.1467-2979.2011.00410.x&link_type=DOI [11]: /lookup/external-ref?access_num=000290540700003&link_type=ISI [12]: #xref-ref-2-1 View reference 2 in text [13]: http://www.ats.aq/e/ep.htm [14]: #xref-ref-3-1 View reference 3 in text [15]: #xref-ref-4-1 View reference 4 in text [16]: #xref-ref-5-1 View reference 5 in text [17]: http://www.ats.aq/documents/ats/treaty_original.pdf

The tide predictions for D-Day

Based on the physics of Newton and Laplace, the big brass tide-predicting machine designed by Lord Kelvin was crucial for the success of the Normandy invasion in World War II.

Interpolation of Tidal Levels in the Coastal Zone for the Creation of a Hydrographic Datum

Abstract As part of the U.K. Hydrographic Office (UKHO)-sponsored Vertical Offshore Reference Frames (VORF) project, a high-resolution model of lowest astronomical tide (LAT) with respect to mean sea level has been developed for U.K.–Irish waters. In offshore areas the model relies on data from satellite altimetry, while in coastal areas data from a 3.5-km-resolution hydrodynamic tide-surge model and tide gauges have been included. To provide for a smooth surface and predict tidal levels in unobserved areas, the data have been merged and interpolated using the thin plate spline method, which has been appropriately tuned by an empirical prediction test whereby observed values at tide gauges were removed from the solution space and surrounding data used to predict its behavior. To allow for the complex coastal morphology, a sea distance function has been implemented within the data weighting, which is shown to significantly enhance the solution. The tuning process allows for independent validation giving a standard error of the resulting surface of 0.2 m for areas with no tidal observations.

A New Methodology for Incorporating Tide Gauge Data in Sea Surface Topography Models

As part of the Vertical Offshore Reference Frames (VORF) project sponsored by the U. K. Hydrographic Office, a new model for Sea Surface Topography (SST) around the British Isles has been developed. For offshore areas (greater than 30 km from the coast), this model is largely derived from satellite altimetry. However, its accuracy and level of detail have been enhanced in coastal areas by the inclusion of not only the 60 PSMSL tide gauges with long-term records around the coasts of the United Kingdom and Ireland but also some 385 gauges established at different epochs and for different observation spans by the U. K. Admiralty. All tide gauge data were brought into a common reference frame by a combination of datum models and direct GPS observations, but a more significant challenge was to bring all short-term sea level observations to an unbiased value at a common epoch. This was achieved through developing a spatial-temporal correlation model for the variations in mean sea level around the British Isles, which in turn meant that gauges with long-term observation spans could be used as control points to improve the accuracy of Admiralty gauges. It is demonstrated that the latter can contribute point observations of mean sea level (MSL) with a precision of 0.078 m. A combination of least squares collocation and interpolation was developed to merge the coastal point and offshore gridded data sets, with particular algorithms having to be developed for different configurations of coastal topology. The resulting model of sea surface topography is shown to present a smooth transition from inshore coastal areas to offshore zones. Further benefits of the techniques developed include an enhanced methodology for detecting datum discontinuities at permanent tide gauges.

Improved bathymetric datasets for the shallow water regions in the Indian Ocean

Ocean modellers use bathymetric datasets like ETOPO5 and ETOPO2 to represent the ocean bottom topography. The former dataset is based on digitization of depth contours greater than 200 m, and the latter is based on satellite altimetry. Hence, they are not always reliable in shallow regions. An improved shelf bathymetry for the Indian Ocean region (20°E to 112°E and 38°S to 32°N) is derived by digitizing the depth contours and sounding depths less than 200 m from the hydrographic charts published by the National Hydrographic Office, India. The digitized data are then gridded and used to modify the existing ETOPO5 and ETOPO2 datasets for depths less than 200 m. In combining the digitized data with the original ETOPO dataset, we apply an appropriate blending technique near the 200 m contour to ensure smooth merging of the datasets. Using the modified ETOPO5, we demonstrate that the original ETOPO5 is indeed inaccurate in depths of less than 200 m and has features that are not actually present on the ocean bottom. Though the present version of ETOPO2 (ETOPO2v2) is a better bathymetry compared to its earlier versions, there are still differences between the ETOPO2v2 and the modified ETOPO2. We assess the improvements of these bathymetric grids with the performance of existing models of tidal circulation and tsunami propagation.

Multiscale ENC Data Management on an Archipelagic Sea Area – Example of the East Adriatic Coast

This paper briefly outlines the production of electronic nautical charts (ENC) as a digital nautical chart, produced by the Croatian National Hydrographic Office (HO) to International Hydrographic Organization (IHO) specifications S-57 Edition 3.1. The production of ENCs is based on the theory of multiscale data management (usage bands). Multiple representations of ENC data are controlled by scale minimum (SCAMIN) attributes. A solution to the problem of multiscale data management as a part of ENC data production for archipelagic sea areas, using the East Adriatic Coast as an example is presented. This solution is based on a long-standing experience in the production of paper charts and recent ENC production for the eastern coast of the Adriatic Sea, which is believed to be the second largest archipelagic area in the Mediterranean. Finally, a new usage band scale range, compilation scale for all navigational purposes and method of using SCAMIN attributes for archipelagic seas are proposed.

Oceanographers and the Cold War: Disciples of Marine Science (review)

Reviewed by: Oceanographers and the Cold War: Disciples of Marine Science Gary E. Weir (bio) Oceanographers and the Cold War: Disciples of Marine Science. By Jacob Darwin Hamblin. Seattle: University of Washington Press, 2005. Pp. xxix+346. $50. Covering 70 percent of the planet, the ocean's benign blue suggests to the extraterrestrial viewer a natural unity that humankind has sought, but never found. Most of us grew up regarding the word ocean not as part of a dynamic whole, but rather as the sum of more particular regional parts. Too often, we understand one or two trees, but have little sense of how they relate to the forest. In Oceanographers and the Cold War, Jacob Hamblin would have us appreciate the history of the ocean sciences in the same way. He claims that postwar oceanography had a "cold war" side and then quite another face with an international focus that was driven by individual scientists. He also informs us that international initiatives represented the most ambitious efforts in oceanography during the first two cold war decades. The sources necessary for this study will support neither of these statements. Most of them are not classified. I have seen them. Hamblin has not. As historians, we cannot understand the Atlantic Ocean in isolation. Neither can we separate the international from the national, or from the cold war that plagued them both, or from the scientists who searched for truth while serving multiple, often conflicting civilian and military masters. Hamblin repeatedly cites the role of the Soviet–United States conflict as a challenge to the international programs he describes, but we are never treated to an analysis of the very tight scientific-political-military dynamic driving it all. More importantly for the present review is the inescapable conclusion that he cannot treat his international programs as part of an already potent dynamic because he did not take the time to look at the fundamental sources that would compel him to do so. Although the Office of Naval Research (ONR) correctly and frequently appears in his story as a major influence, Hamblin never consulted the ONR records in RG-298 at the U.S. National Archives and the Washington National Records Center in Suitland, Maryland. Large portions of them are critical, applicable, and unclassified. Neither did he tap the U.S. Navy Hydrographic Office files in RG-37 at the National Archives. That collection holds the primary source material for ocean-bottom surveys conducted by civilian and naval teams worldwide during the cold war. Much of this emerged from classification even as I studied the collection during the late 1990s. Here, for example, Hamblin would have found Project Cabot, Richard Fleming's collaboration with the Canadians in one of the first truly synoptic studies of the Gulf Stream. Save for some strategic plans files available at the Naval Historical Center, naval records played no role in Hamblin's study, even though the ONR reigned as the premier [End Page 239] patron of U.S. oceanography both nationally and internationally from 1946 to well after the foundation of the National Science Foundation (NSF). Neither did he take advantage of nearly a dozen oral histories at the Naval Historical Center by major figures in his story. This reaches the level of the absurd when Hamblin calls James Wakelin an "admiral" even though this physicist and policy maker never served in the navy. Wakelin's professional biography is available at the Naval Historical Center because of his tenure as assistant secretary of the navy for research and development. Is Hamblin aware, however, that the eminent Harry Hess was an admiral in the naval reserve? This problem extends beyond naval sources. The time spent defining both oceanography's nature and its future helped determine the dynamic that drove ocean science and its international ambitions after 1945. The war had prompted leaders in the field to refine the definition beyond that crafted by Henry Bigelow in 1930. The National Academy of Sciences' archive holds a verbatim transcript of the so-called Wardman Park Meeting in 1949, the source for Oceanography 1951, written primarily by Carl Eckart. This gathering defined a great many of oceanography's identity problems domestically...

FROM PRIVATE TO OFFICIAL HYDROGRAPHY: THE CHARTS AND SAILING DIRECTIONS OF JOSEPH DESSIOU (1743–1822) AND HIS SON, JOSEPH FOSS DESSIOU (1769–1853)

Joseph Foss Dessiou (1769–1853) is known as a compiler of charts and sailing directions during the first quarter of the nineteenth century, and also for work for the Hydrographic Office in the latter part of his life, particularly on the computation of tides. It has not been widely appreciated that his father, Joseph Dessiou (1743–1822), was also a hydrographer. In addition his son, Joseph Foss Dessiou, junior (1792–1818), who drowned while surveying, became a third member of the family to enter the profession. This article is concerned with the work of the two older Dessious who both undertook surveys during their seagoing careers as masters and in later life turned to chart compilation for commercial publishers. The similarity in their names, and the overlap in their active lives, have resulted in some confusion between them. However an examination of all their work shows that their publishers appreciated the need to distinguish them and used the ascriptions Joseph Dessiou or J. Dessiou, and Joseph Foss Dessiou, or J. F. Dessiou correctly. When their work is attributed on this basis a logical pattern emerges of their interests and contacts during their working lives in private chart publishing. Their careers mirror the changes in chart production that took place between one generation and the next. The father started his career with a survey and chart of his home waters for local interests, a common eighteenth-century pattern, while the son ended his with employment in the Hydrographic Office and the inclusion of some of the charts he had drawn for commercial publication in the official Admiralty catalogue. During the transition from private to public chart production in the first two decades of the nineteenth century both father and son worked as chart compilers for rival private chart publishers. The Hydrographic Office at this time was still in its infancy. The Dessious’ charts and sailing directions are listed in the Appendix to this article, with full details and locations of examples of each.

Geomorphology and surficial sediments of the southeast Australian continental margin

The southeast Australian continental margin stretches 1500 km north from Bass Strait to the Great Barrier Reef. This part of the Australian margin represents a distinct oceanographic, climatic and geological province. Recent initiatives by the Australian Hydrographic Office, Geoscience Australia and the Environmental Geoscience Group at the University of Newcastle have provided a new digital database of bathymetric soundings and surface‐sediment distribution for the southeast Australian margin. This database is used here to provide the first detailed digital 3–D representations of the southeast Australian margin, leading to new morphological classifications and integrated sedimentation models. As a result of its tectonic history of asymmetric passive margin rifting, the continental margin as a whole is narrow, steep and sediment deficient. The shelf can be divided into an inner zone with bedrock cropping out or close to the surface, and an outer zone that represents the top of a Cenozoic sediment wedge. The continental shelf and slope can be classified into a variety of morphological units based on detailed analysis of geometry and slope. These units include a succession of shore‐normal zones (shoreface, inner plain, inner and mid‐slope, outer plain and continental slope) and a number of local regions (mounds, lobes, tongues, depressions, deltas and bedrock). Sediments are generally siliciclastic in composition on the inner margin and carbonate‐rich on the outer margin, reflecting carbonate production at low sea‐levels on the outer shelf/continental slope and terrestrial sediment input to the inner shelf. Fine‐grained sediments are rare on the shelf north from Port Stephens, and occur draped across the inner and mid‐slope further south. Outer shelf carbonate sediments are coarse grained with a patchy distribution related to winnowing by the East Australian Current. The East Australian Current also produces erosional depressions and southward prograding sediment tongues and lobes where it separates from the shelf off Port Stephens. The margin character varies markedly from south to north in terms of fine‐sediment distribution, depth to the shelf break and width of the outer shelf. These outer shelf features reflect an inherited palaeotopography from underlying Cenozoic sediment wedges that are better developed on the southern margin.

First- and higher-order dynamical controls on water exchanges between tidal basins and the open ocean. A case study for the East Frisian Wadden Sea

Observational data, high-resolution numerical modelling results and a simple analytical theory are combined in this paper to demonstrate the dependence of the volume transports through tidal inlets on topographical or morphological parameters of a Wadden Sea system. The area of interest covers the East Frisian Wadden Sea and consists of seven weakly connected tidal basins. The observations include time series of tidal gauge data and surface currents measured at a pile station in the backbarrier basin of the island Langeoog, as well as several ADCP transects in the Accumer Ee tidal inlet. The numerical simulations are based on the 3-D primitive equation General Estuarine Transport Model (GETM) with a horizontal resolution of 200 m and terrain following vertical coordinates. The model is forced at its open boundaries with sea-level data from an operational model for the German Bight (German Hydrographic Office). The simple theoretical concepts presented illustrate the effect of topography (hypsometry) in the tidal basins on the temporal variability of the exchange of water. This topographic control is effectuated through the bottom slope in the areas prone to drying and flooding. For our study area it takes about twice as long from slack water to maximum flood current than from slack water to maximum ebb current. The underlying physics of this signal modulation from a more or less harmonic forcing at the open-sea boundary and the quantification of the contributing physical processes are the major results of this paper. Estimates based simply on volume conservation are consistent with observations and results from numerical modelling, but they do not completely capture the actual non-linear tidal response. Our analysis shows that at least during part of the tidal cycle characteristic topographic parameters of the inlet/bay system have a major impact on the rate of exchange of waters between the Wadden Sea and the open ocean. This impact is especially strong during the transition between flood and ebb conditions. The possible morphodynamic responses are also addressed focusing on some common (“universal”) topographic features in seven tidal basins.

On the circulation in the East Frisian Wadden Sea: numerical modeling and data analysis

In this paper we use a combination of nu- merical modeling and data analysis to gain a better understanding of the major characteristics of the circu- lation in the East Frisian Wadden Sea. In particular, we concentrate on the asymmetry of the tidal wave and its modulation in the coastal area, which results in a com- plex pattern of responses to the sea-level forcing from the North Sea. The numerical simulations are based on the 3-D primitive equation General Estuarine Transport Model (GETM) with a horizontal resolution of 200 m and terrain-following vertical coordinates. The model is forced at its open boundaries with sea-level data from an operational model for the German Bight (German Hydrographic Office). The validation data for our model simulations include time series of tidal gauge data and surface currents measured at a pile in the back-barrier basin of the Island Langeoog, as well as several ADCP transects in the Accumer Ee tidal inlet. Circulation and turbulence characteristics are inves- tigated for typical situations driven by spring and neap tides, and the analysis is focused on dominating tem- poral and spatial patterns. By investigating the response of five back-barrier basins with rather different mor- phologies to external forcing, an attempt is made to elucidate the dominating physical balances controlling the circulation in the individual sub-basins. It is dem- onstrated that the friction at the seabed tends to slow down the tidal signal in the shallow water. This leads to the establishment of flood dominance in the shallowsea north of the barrier islands. South of the islands, where the water volume of the channels at low tide is smaller than the tidal prism, the asymmetry of the tidal signal is shifted towards ebb dominance, a feature which is par- ticularly pronounced at spring tide. At the northern open boundary, the tidal wave propagating from west to east generates a sea-level dif- ference of � 1 m along the boundary, and thereby trig- gers vigorous alongshore currents. The frictional control in the model is located in the inlets, as well as along the northern boundary. The correlation between velocity and turbulent kinetic energy tends to the establishment of a net southward transport, giving theoretical support to the observed accumulation of sediments on the in- tertidal flats. Weak turbulence along the northern shores of the barrier islands and the small magnitude of the residual currents there promote accumulation of sus- pended matter in these areas, although wave action will generally counteract this effect.

Improbable warriors: women scientists and the U.S. Navy in World War II

At the outbreak of World War II, four scientists left their comfortable college teaching positions to work for the government. Three served in uniform, the fourth oversaw contracts for the Navy. Such dramatic changes in life styles during the period were common -- for men. But these established scientists were women, and each made significant contributions to a Navy embroiled in a modern, science-dependent war. Mary Sears, a Woods Hole Oceanographic Institution planktonologist, headed the Hydrographic Office's Oceanographic Unit. Grace Hopper, a Yale-trained mathematician, went to the Bureau of Ships Computation Laboratory at Harvard where she worked on one of the first computers, churning out essential data for ordnance and other projects. Florence van Straten, a New York University chemist, served as an aerological engineer analyzing the use of weather in combat. Mina Rees was the chief technical aide to the applied mathematics panel of the National Defense Research Committee. This book firmly places the women within the context of their times. Deeply rooted in previously unexamined primary sources, the work helps readers understand the personal and professional experiences of women in the military and the attitudes they faced, and fully appreciate the educational and occupational barriers faced by women scientists in the 1930s and 1940s.The author focuses on their efforts during the war, but also discusses the women's skills and training, tells how they came to war work, and examines the contributions they made once there. She further considers how the war changed their lives, especially their professional lives, and how it affected their future careers. While other books havebeen written about women in the military, this is the first to focus on Navy women scientists.

HISTORY OF HYDROGRAPHIC RESEARCH IN SWEDEN

Hydrographic investigations in the 18th and 19th centuries are briefly described. An extensive investigation of the Baltic Sea was performed in 1877. Regular observations of temperature, salinity, and currents were started on Swedish lightships and coastal stations in 1878. The different hydrographic organizations and scientists are presented. In 1893 the Swedish Hydro- graphic Commission, from 1902 the Hydrographic-Biological Commission, was formed. The complicated relations between the Oceanographic Institution at the University of Goteborg, the Oceanographic Institute, and the Hydrographic-Biological Commission are explained. Some world- famous oceanographers and their works are presented. The Commission was dissolved in 1948 and the Board of Fisheries of Sweden was formed, taking over its responsibilities. The hydrographic investigations were assigned to the Hydrographic Department of the Board of Fisheries. The development of the Hydrographic Department and its transfer to the Swedish Meteorological and Hydrological Institute are described. The work of the Fisheries Bureau and the Navy Hydrographic Office are briefly explained.

Implications of the use of GNSS and WGS84 for Marine Navigation

For the last two years a large collaborative project has been taking place at the University of Nottingham to investigate novel strategies for the implementation of GNSS within all phases of marine navigation in UK waters. The project, which was recently completed, was funded by the Engineering and Physical Sciences Research Council. The project also received financial support from a prestigious team of collaborators that included the UK Ministry of Defence Hydrographic Office, Trinity House Lighthouse Service, Northern Lighthouse Board, Commissioners for Irish Lights and the Port of London Authority. The first phase of this project was reported in the Journal in May 1999 (Ashkenazi et al., 1999); this paper presents an update of the progress of the project over the last year.

Classification, grainsize relations and sediment distributions inferred from visual sediment descriptions on RAN Hydrographic Office bathymetry charts of the northern Great Barrier Reef lagoon

The marine sediments of Australia's continental shelves have been sparsely sampled by geological expeditions. However, there exist many qualitative descriptions of the seabed, made from visual and tactile examination of wet surficial samples, on Royal Australian Navy Hydrographic Office bathymetry charts. The reliability and geological meaning of the visual descriptions do not seem to have been investigated, making their suitability as bottom classifiers unknown. Classification schemes were devised for the descriptions, which are in a symbol form suitable for computer manipulations. The schemes were applied to nearly 5000 descriptions for the Great Barrier Reef lagoon area from Cape Flattery to Whitsunday Islands, where several sediment types are interleaved. The visual descriptions formed a consistent and reliable dataset at regional and smaller scales. Coherent surficial sediment distribution patterns were derived that closely match trends of grainsize distributions in some test areas, but which indicate that the present broadly known patterns for the Great Barrier Reef are in need of revision, particularly in coastal areas and embayments. Broad quantitative correlations were established against grainsize for several key visual descriptions, greatly enhancing their usefulness. The visual descriptions form a database of unique character, more useful than simple grainsize descriptions for many purposes. Sediment charts derived from them match everyday expectations of the in situ appearance and texture of sediments described as mud and sand in the marine environment, whereas various geological grainsize nomenclatures do not. A grainsize triangle is constructed relating the visual descriptions of wet marine surficial sediments to mud, sand and gravel size percentage weights.

GNSS & WGS 84 for Marine Navigation in UK Waters

The following paper reports on the progress of a large collaborative project in the UK to investigate novel strategies for the implementation of GNSS within all phases of marine navigation. The project is funded by the UK Government (Engineering and Physical Sciences Research Council) under the leadership of the IESSG at the University of Nottingham. The project receives the support from a prestigious team of collaborators which include the UK Ministry of Defence Hydrographic Office, Trinity House Lighthouse Service, Northern Lighthouse Board, Commissioners for Irish Lights and the Port of London Authority. This consortium is of strategic importance, as their operations encompass the provision of aids to navigation for all phases of marine transport within the UK and elsewhere.

Digital Charting, Now and in the Future

The views expressed in this paper are personal to the author, and not intended to represent official policy of the UK Hydrographic Office.With the ever increasing use of electronic charts in the small craft sector, this paper is designed to give some background to developments at the United Kingdom Hydrographic Office. Included is a short review of the state of the market, with the author's view of possible future progression. The various formats of data are discussed, with a summary of the legislative background within the commercial market. This discussion is relevant, as it will ultimately shape the future market for small craft users

Digital charting: a Royal Navy navigator's view

The IMO have given their approval to the concept of an electronic chart display and information system (ECDIS) (IMO Assembly resolution A.817(19)) but the detailed technical specification required for Type Approval is still to be completed. Meanwhile, the approved 'vector data' required for ECDIS is only just beginning to be available and its form is still evolving. The Royal Navy is moving towards adoption of this new technology and has mandated its use for a future class of frigate. It is already involved in trials of prototype equipment, albeit using a (raster) data format which has yet to receive international approval. Trials supported by UK manufacturers and the UK Hydrographic Office are proving beneficial to all involved and vector data was incorporated during 1996. The need to strike a balance between adapting current navigation techniques to the electronic era and devising new ones has already been recognised, as is the inevitable impact on training. The ability to measure positions, bearings and distances far more accurately than ever before is putting the hydrographers on their mettle, while the need to understand and correctly apply datum shifts and match projections when displaying different forms of data is posing a new challenge for the navigator. The end of the paper chart in the RN may be forecastable but is not yet in sight and there are a number of questions that need to be resolved before ECDIS becomes accepted as the prime method of navigation.

All at Sea: An Exhibition to Celebrate Two Hundred Years of the Hydrographic Office

All at Sea: An Exhibition to Celebrate Two Hundred Years of the Hydrographic Office

The Geocoding of Synthetic Aperture Radar Imagery and an Application to Nautical Charting

An ERS‐1 SAR image of Frankfurt was geocoded using a variety of DEM spatial resolutions to examine the influence on positional accuracy compared with control points derived from a 1:50 000 scale map of the same area. It was demonstrated that mapping to 1:50 000 scale was possible in flat areas with a DEM resolution finer than 200 m.The case for SAR imagery in nautical charting is discussed in the light of these results, drawing on recent experiences at the Hydrographic Office in charting the South Orkney Islands.